Aircraft covering



No Drawing.

Patented Apr. 1, 1930 uNrTsn STATES PATENT OFFICE ISADOBE M. JACOBSOHN, OF CHICAGO, ILLINOIS, AND STARE TRUSCOTT, OF BIRMING- RAM,

OHIO

AIRCRAFT COVERING This invention relates to a gas retaining fabric for aircraft coverings using an impermeable film prepared from a mixture of cuprammonium cellulose or the like and a latex.

It is, however, to be understood that Without material modification the fabric is applicable to various other uses and applications.

The disadvantages of a gas retaining fabric using) goldbeaters skin as an impermeable mem rane are well known to those skilled in the art and the present invention is intended to overcome various disadvantages incident to the preparation of such skins.

It has been found that a film produced from a mixture of cuprammonium cellulose or other water soluble form of cellulose, and latex has a very high resistance to the passage of the buoyant gases. Such material "can be produced either in large sheets or spread directly upon cloth in a manner similar to that by which rubber is applied.

The following will illustrate the method of preparing gas impermeable fabrics from a mixture of cuprammonium cellulose and latex. Dissolve 0.29 gm. of tetramethyl thiuram disulfide in 15 cc. of hot acetone. Add this solution quickly to 400 cc. of water at 20 C. This is immediately followed by the addition, with vigorous agitation, of 70 gms. of rubber latex containing 40% of solid matter. It is essential that this operation be carried out Very promptly in order to prevent the coagulation of the first material added. Three gms. of zinc sulfate, dissolved in 10 cc. of water, are treated with 7 cc. of ammonia water containing 29% of ammonia. The white precipitate formed at first should be completely dissolved before proceeding further. This solution is then added to the latex solution above, with vigorous agitation. 250 ms. of cuprammonium cellulose are then a ded to the mixture and stirred until a homogeneous mixture results. The cuprammonium cellulose-latex mixture prepared by the above method should be'ke t at a temperature not exceeding 20 C. until applied.

In order to prepare a gas impermeable fabric from the cuprammonium cellulose-latex Application filed March 5, 1926. Serial No. 92,645.

mixture, it is spread upon a balloon cloth, spreading in 8 to 15 coats, depending upon the permeability desired. Each coat is dried by the passage over its surface of a current of air, heated to.40' C. before the application of the next coat. When the last coat is dry,

the fabric is immersed in a 2% solution of sulfuric acid in order to dissolve the copper oxide which is deposited with the film. The fabric is then washed thoroughly with water and finally immersed in a 15% solution of glycerine. The fabric is then air dried. The immersion in a solution of glycerine renders the material plastic, permitting creasing or folding without its-being subjected to cracking or breaking.

It is thus seen that the present invention (omprehends a simple and practical fabric suitable as a substitute for goldbeaters skin and well adapted to accomplish, among others, the various objects and advantages herein set forth.

The invention herein described may be manufactured and used by or for the Government of the United States for governmental purposes without the payment to us of any royalty thereon or therefor.

\Vhat we claim is 1. A fabric coated with a film of reverted cuprammonium cellulose-latex immersed in glycerine whereby the fabric is rendered flexible and impermeable to gases.

2. A method of rendering a fabric flexible and impermeable to gases consisting in coating a fabric with a mixture of cuprammonium cellulose-latex, bathing the coated fabric in 

